Optimization of parameters for binary genetic algorithms.

In the GA framework, a species or population is a collection of individuals or chromosomes, usually initially generated randomly. A predefined fitness function guides selection while operators like crossover and mutation are used probabilistically in order to emulate reproduction.Genetic Algorithms (GAs) belong to the field of evolutionary computation which is inspired by biological evolution. From an engineering perspective, a GA is an heuristic tool that can approximately solve problems in which the search space is huge in the sense that an exhaustive search is not tractable. The appeal of GAs is that they can be parallelized and can give us "good" solutions to hard problems.One of the difficulties in working with GAs is choosing the parameters---the population size, the crossover and mutation probabilities, the number of generations, the selection mechanism, the fitness function---appropriate to solve a particular problem. Besides the difficulty of the application problem to be solved, an additional difficulty arises because the quality of the solution found, or the sum total of computational resources required to find it, depends on the selection of the parameters of the GA; that is, finding a correct fitness function and appropriate operators and other parameters to solve a problem with GAs is itself a difficult problem. The contributions of this dissertation, then, are: to show that there is not a linear correlation between diversity in the initial population and the performance of GAs; to show that fitness functions that use information from the problem itself are better than fitness functions that need external tuning; and to propose a relationship between selection pressure and the probabilities of crossover and mutation that improve the performance of GAs in the context of of two extreme schema: small schema, where the building block in consideration is small (each bit individually can be considered as part of the general solution), and long schema, where the building block in consideration is long (a set of interrelated bits conform part of the general solution).Theoretical and practical problems like the one-max problem and the intrusion detection problem (considered as problems with small schema) and the snake-in-the-box problem (considered as a problem with long schema) are tested under the specific hypotheses of the Dissertation.The Dissertation proposes three general hypotheses. The first one, in an attempt to measure the impact of the input over the output, study that there is not a linear correlation between diversity in the initial population and performance of GAs. The second one, proposes the use of parameters that belong to the problem itself to joint objective and constraint in fitness functions, and the third one use Holland's Schema Theorem for finding an interrelation between selection pressure and the probabilities of crossover and mutation that, if obeyed, is expected to result in better performance of the GA in terms of the solution quality found within a given number of generations and/or the number of generations to find a solution of a given quality than if the interrelation is not obeyed

Approximate Analytical Solutions to the Initial Data Problem of Black Hole Binary Systems

We present approximate analytical solutions to the Hamiltonian and momentum constraint equations, corresponding to systems composed of two black holes with arbitrary linear and angular momentum. The analytical nature of these initial data solutions makes them easier to implement in numerical evolutions than the traditional numerical approach of solving the elliptic equations derived from the Einstein constraints. Although in general the problem of setting up initial conditions for black hole binary simulations is complicated by the presence of singularities, we show that the methods presented in this work provide initial data with $l_1$ and $l_\infty$ norms of violation of the constraint equations falling below those of the truncation error (residual error due to discretization) present in finite difference codes for the range of grid resolutions currently used. Thus, these data sets are suitable for use in evolution codes. Detailed results are presented for the case of a head-on collision of two equal-mass M black holes with specific angular momentum 0.5M at an initial separation of 10M. A straightforward superposition method yields data adequate for resolutions of $h=M/4$, and an "attenuated" superposition yields data usable to resolutions at least as fine as $h=M/8$. In addition, the attenuated approximate data may be more tractable in a full (computational) exact solution to the initial value problem.Comment: 6 pages, 5 postscript figures. Minor changes and some points clarified. Accepted for publication in Phys. Rev.

Neonatal ureteral obstruction stimulates recruitment of renin-secreting renal cortical cells

Neonatal ureteral obstruction stimulates recruitment of renin-secreting renal cortical cells. Unilateral ureteral obstruction (UUO) in the neonate increases ipsilateral renal renin gene expression, an effect which is mediated by renal nerves. To determine whether neonatal UUO alters the number of renal cortical cells secreting renin and whether this change is modulated by renal nerve activity, newborn Sprague-Dawley rats were subjected to left UUO, right uninephrectomy, or sham operation and studied four weeks thereafter. To evaluate the importance of renal nerves in this response, an additional group of animals underwent chemical sympathectomy with guanethidine. Ureteral obstruction was associated with marked reduction in renal mass in the obstructed kidney and contralateral compensatory hypertrophy, changes which were not altered by sympathectomy. Renin messenger RNA and renal renin content were elevated in the obstructed kidney. The number of cells secreting renin, measured by the reverse hemolytic plaque assay, was markedly increased in the obstructed kidney (45 ± 18 plaques/slide vs. 11 ± 1 plaques/slide in sham animals), but not in the opposite kidney or following uninephrectomy. This effect was not significantly altered by sympathectomy. There was no change in the amount of renin secreted per cell or in the secretory response to Ca++. These results show that UUO results in recruitment of cells not previously secreting renin by a mechanism independent of renal nerve activity. This recruitment occurs without alteration of the quantity of renin secreted per cell or in the normal regulatory effect of Ca++ on renin secretion. An increase in the number of renin-secreting cells may contribute to the activation of the renin-angiotensin system, and thus to the vasoconstriction observed following ureteral obstruction

Reliability and reproductibility of skin temperature of overweight subjects by an infrared thermograpy software designed for human beings

The technical improvement and new applications of Infrared Thermography (IRT) with healthy subjects should be accompanied by results about the reproducibility of IRT measurements in different popula-tion groups. In addition, there is a remarkable necessity of a larger supply on software to analyze IRT images of human beings. Therefore, the objectives of this study were: firstly, to investigate the reproducibility of skin temperature (Tsk) on overweight and obese subjects using IRT in different Regions of Interest (ROI), moments and side-to-side differences (?T); and secondly, to check the reliability of a new software called Termotracker®, specialized on the analysis of IRT images of human beings. Methods: 22 overweight and obese males (11) and females (11) (age: 41,51±7,76 years; height: 1,65±0,09 m; weight: 82,41±11,81 Kg; BMI: 30,17±2,58 kg/m²) were assessed in two consecutive thermograms (5 seconds in-between) by the same observer, using an infrared camera (FLIR T335, Sweden) to get 4 IRT images from the whole body. 11 ROI were selected using Termotracker® to analyze its reproducibility and reliability through Intra-class Correlation Coefficient (ICC) and Coefficient of Variation (CV) values. Results: The reproducibility of the side-to-side differences (?T) between two consecutive thermograms was very high in all ROIs (Mean ICC = 0,989), and excellent between two computers (Mean ICC = 0,998). The re-liability of the software was very high in all the ROIs (Mean ICC = 0,999). Intraexaminer reliability analysing the same subjects in two consecutive thermograms was also very high (Mean ICC = 0,997). CV values of the different ROIs were around 2%. Conclusions: Skin temperature on overweight subjects had an excellent reproducibility for consecutive ther-mograms. The reproducibility of thermal asymmetries (?T) was also good but it had the influence of several factors that should be further investigated. Termotracker® reached excellent reliability results and it is a relia-ble and objective software to analyse IRT images of humans beings

Stereovideo youtube channel: short educational videos for the on-line learning of the the stereographic projection technique in Structural Geology

Stereovideo channel https://www.youtube.com/user/geostereovideo) is a YouTube channel of short educational videos (<5 min) focused on learning the handling of the stereographic projection technique applied to Structural Geology (also to Engineering Geology). This type of videos aims to reinforce the traditional classroom lessons with the use of communication technologies resources. Such a einforcing facilitates the possibility to deepen more on conceptual aspects once the students dominate the representation tool helping them to develop their own critical thinking skills. After three years of being launched on-line (on 2014), we analyze the broadcast and acceptance of the channel by the academic community. For this purpose we have taken into account two different sources: (1) the analytics tool from YouTube (subscriptions, views, countries, comments from the users, type of device for viewing), and (2) our own survey among users (students and teachers) to get their opinion about the videos. By January, 2017 (date of sending of this abstract), the channel has a total of 650 subscriptions, with more than 85,000 views all around the world, mainly in Spanish speaking countries (as the videos are in Spanish). The main devices for viewing the videos are PCs, but is noteworthy the use of smart phones and tablets. The video users, both students and teachers, value this type of content positively

Stereovideo youtube channel: short educational videos for the on-line learning of the the stereographic projection technique in Structural Geology

Stereovideo channel https://www.youtube.com/user/geostereovideo) is a YouTube channel of short educational videos (<5 min) focused on learning the handling of the stereographic projection technique applied to Structural Geology (also to Engineering Geology). This type of videos aims to reinforce the traditional classroom lessons with the use of communication technologies resources. Such a einforcing facilitates the possibility to deepen more on conceptual aspects once the students dominate the representation tool helping them to develop their own critical thinking skills. After three years of being launched on-line (on 2014), we analyze the broadcast and acceptance of the channel by the academic community. For this purpose we have taken into account two different sources: (1) the analytics tool from YouTube (subscriptions, views, countries, comments from the users, type of device for viewing), and (2) our own survey among users (students and teachers) to get their opinion about the videos. By January, 2017 (date of sending of this abstract), the channel has a total of 650 subscriptions, with more than 85,000 views all around the world, mainly in Spanish speaking countries (as the videos are in Spanish). The main devices for viewing the videos are PCs, but is noteworthy the use of smart phones and tablets. The video users, both students and teachers, value this type of content positively